1. Field of the Invention
This invention relates to a novel method for the production of 1,3-dioxolanes useful as a solvent, an intermediate for medicines, and a raw material for acetal resin, for example.
2. Description of the Prior Art
In the conventional methods for the production of 1,3-dioxolanes, the method resorting to the cyclization of a glycol with an aldehyde or a ketone and the method resorting to the cyclization of an alkylene oxide with an aldehyde or a ketone have been known.
As respects the production of a 1,3-dioxolane by the cyclization of a glycol with an aldehyde, it is disclosed in DE-A-1914209 (1970), for example, that the reaction of a glycol with an aqueous solution of formaldehyde in the presence of an acid catalyst produces a 1,3-dioxolane containing 7% by weight of water in a yield of 96.5%.
In JP-A No. 49-62469 (1974), it is disclosed that a 1,3-dioxolane of high purity is obtained by reacting a glycol with paraformaldehyde in the presence of an acid catalyst, adding cyclohexane to the reaction mixture and distillating the resultant mixture.
Then, in Ind. Eng. Chem., 46, 787 (1954), it is disclosed that a 1,3-dioxolane of high purity having only a small water content is obtained by reacting a glycol with paraformaldehyde in the presence of an acid catalyst, adding common salt to the reaction distillate thereby inducing separation of the solution into two phases, and rectifying the organic phase.
In the methods which use such glycols and aldehydes as mentioned above as raw materials, however, since the produced 1,3-dioxolanes form azeotropes with water, the separation and removal of water from such 1,3-dioxolanes cannot be easily attained solely by the step of distillation. The production of a 1,3-dioxolane having high purity and a low water content calls for further steps of purification such as extraction and a salting-out treatment and, therefore, tends to boost the cost of production.
As regards the production resorting to the reaction of an alkylene oxide with an aldehyde, it is disclosed in Ber., 74, 145 (1941) and J. Am. Chem. Sec., 55, 3741 (1933) that a 1,3-dioxolane is obtained in a yield of 22 to 63% by performing the reaction in the presence of stannic chloride. It is disclosed in Ann., 710, 85 (1967) that this reaction, when performed in the presence of a quaternary ammonium salt as a catalyst, produces a 1,3-dioxolane in a yield of 36 to 85%.
The methods of production disclosed in these articles of literature, however, have not been fully developed to the extent of finding commercial utility because they have problems of insufficient yield of reaction, difficulty in recovery of used catalyst for re-use, and short service life of catalyst in spite of their freedom from the problem of dehydration of the produced 1,3-dioxolanes.
An object of this invention, therefore, is to provide a novel method for the production of a 1,3-dioxolane.
Another object of this invention is to provide a novel method for producing a 1,3-dioxolane of high purity having only a small water content in a high yield easily solely by a step of distillation.